Heliostats

At what are known as tower power plants, thousands of mirrors direct the sun’s rays onto a central receiver at the top of a tower.

The prerequisite for high yields is direct solar radiation, which occurs mainly in the Earth’s sun belt. A particularly high number of CSP plants have been and are being built in countries such as Spain and the United States, as well as the Middle East and North Africa. In these plants, the energy captured by concentrating solar power can be boosted further by large heat reservoirs containing liquid salt, that holds in the heat already obtained – for times when the sun does not shine.

Thermal energy from solar power

What is billions of years old and still full of power? The sun. Photovoltaic and solar thermal power technologies use the Earth’s closest star as a literally inexhaustible source of energy. While photovoltaic uses solar cells to convert sunlight directly into electricity, solar thermal power technology produces thermal energy. In private homes, solar thermal power is used mainly to provide hot water and well-heated rooms. Meanwhile, concentrating solar power – CSP for short – can produce electricity on a large scale: a solar thermal power plant such as Noor I in Morocco has a capacity of 160 megawatts (MW) and supplies electricity for 350,000 households. Thousands of mirrors concentrate the sunlight and warm up a liquid. This source of heat then turns water into steam, which subsequently produces electricity through a generator. Four different types of collectors are used to concentrate the sun’s rays:

New investment and a jobs boom?

According to the study “Solar Thermal Electricity – Global Outlook 2016,” countries such as Morocco are thus making an important contribution to reducing emissions of green-house gases. By 2020 the countries in the “sunbelt” – those located between 40° north and south of the equator – could avoid 32 million metric tons of CO2 by using CSP. At present, Spain and the United States are top of the table for CSP capacity, but other countries are catching up. China aims to commission solar thermal power plants with a total capacity of 10 gigawatts (GW) by 2020, and Saudi Arabia is planning a CSP capacity of 25 GW by 2032. The study, which was commissioned by SolarPACES, a technology program of the International Energy Agency (IEA), Greenpeace and the European Solar Thermal Electricity Association (ESTELA), also found that the use of this climate-neutral energy source in these countries would create investments worth €16 billion by 2020 and 70,000 new jobs in the future.